• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Smallest tool size milling slotted holes

Status
Not open for further replies.

Boncuk

New Member
Hi All,

more and more components are thrown on the market having connecting pins with unsymmetrical measurements like pushbottons and shielded connectors.

E.g. a Scart connector has metal strips of 0.4mm thickness and 2mm length. Drilling a hole of 2mm diameter will not result in the necessary mechanical stability, hence a slotted hole of 0.5 X 2mm would be desirable.

My PCB manufacturer in Bulgaria uses a minimum diameter of 1mm for the milling tool which is still unsatisfactory resulting in unnecessary fills with soldering tin.

I guess he uses this tremendeously oversized tool for safety reasons. Cutting a slotted hole in FR4 material means a lot of stress on the tool. Own experience proves that high cutting speed (longitudinal movement) results in many broken tools, which can only be avoided by extremely slow movement with least stress on the tool.

What is the minimum tool size your PCB manufacturer uses for slotted holes?

Regards

Boncuk
 
Last edited:

duffy

Well-Known Member
I would appreciate a link to your Bulgarian Boardhouse because my guys seem to think even .063" (1.53mm) is just too insanely small to work with.

I hate slots, they f-up everything. No quick turn protos, can't just substitute a bigger round hole.
 

duffy

Well-Known Member
BUNGARD doesn't look like a boardhouse, it looks like an equipment manufacturer.

The very small mill bits have severe cutting rate and handling precautions. You have to move them very slow. You have to use an optical tool end detector because the regular one will break them. There are vibration restrictions and even handling precautions - they break if you drop them on the floor, for instance. The REALLY small ones break if they fall over from standing on end on a hard surface.
 

Boncuk

New Member
I would appreciate a link to your Bulgarian Boardhouse because my guys seem to think even .063" (1.53mm) is just too insanely small to work with.
http://www.bilex-lp.com (Company manager and addressee for questions concerning non standard manufacturing is Mr. Hristo Ginov.)


I hate slots, they f-up everything. No quick turn protos, can't just substitute a bigger round hole.
I hate them too. I had to make 250 PCBs populated with TBA800s with cooling (and ground) fins of 2.5X0.4mm. Made them using a fretsaw, still a PITA. :) or like we use to say in Germany: "a kind of work for somebody who has slain his mother and father." :)

Boncuk
 

Boncuk

New Member
BUNGARD doesn't look like a boardhouse, it looks like an equipment manufacturer.

The very small mill bits have severe cutting rate and handling precautions. You have to move them very slow. You have to use an optical tool end detector because the regular one will break them. There are vibration restrictions and even handling precautions - they break if you drop them on the floor, for instance. The REALLY small ones break if they fall over from standing on end on a hard surface.
I didn't say BUNGARD is a PCB manufacturer. I just wanted to point out that this kind of machining tool is available in Europe.

Drills and machining tools for PCB manufacturing are made of extremely hardended steel which can stand a lot of longitudinal pressure but barely perpendicular force. You can snip apart a 1mm drill to break without much force.

Machining can be done using KAVO drive spindles rotating at ≤100,000 rpm with absolutely no vibration, 100% balanced and extremely slow and constant movement.

Most PCB manufacturers can't afford KAVO drives and use junk machines which are not capable of handling the boards propberly.

Holes of a diameter of 0.05mm can be made in jet engine's turbine blades for cooling (Etching at very high etchant pressure). So it should be possible to seek for a method to make nice slotted holes in PCBs.
 

duffy

Well-Known Member
Made them using a fretsaw, still a PITA.
Get a little tabletop CNC mill for this. It has saved me many headaches.

or like we use to say in Germany: "a kind of work for somebody who has slain his mother and father."
That's a good one, tell me what it is in German - I may want to mutter it under my breath sometimes.
 

Boncuk

New Member
That's a good one, tell me what it is in German - I may want to mutter it under my breath sometimes.
Arbeit für jemanden, der Vater und Mutter erschlagen hat. :D
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top